Tube bending machines



May 30, 1961 A. R. LANDIS TUBE BENDING MACHINES Filed July 9, 1956 5Sheets-Sheet l FIGZ, 90

May 30, 1961 A. R. LANDIS TUBE BENDING MACHINES 3 Sheets-Sheet 2 FiledJuly 9, 1956 I Hull m FIG.4.

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y 1961 A. R. LANDIS 2,986,195

TUBE BENDING MACHINES Filed July 9, 1956 5 Sheets-Sheet 3 3y MM TUBEBENDING MACHINES Alfred R. Landis, St. Johns Station, Mo., asslgnor, bymesne assignments, to Imperial-Eastman Corporation, Chicago, 111., acorporation of Illinois Filed July 9, 1956, Ser. No. 596,561

3 Claims. (Cl. 153-40) impractical in small sizes (for example Vs inchOD), .and tube bending machines designed forsmall sizes of tubing havenot heretofore been readily adaptable to larger sizes (for example inchO.D.).

One of the objects of this invention is to provide a tube bendingmachine in which the tendency of thin-walled tubing being benttocollapse is overcome.

Another object is to provide a compact tube bending machine which may bequickly and easily adapted to bend tubes of various different diameters.

Still another object of this invention is to provide a tube bendingmachine capable of bending tubing of both large and small diameter.

Still another object of this invention is to provide a tube bendingmachine with a rotating radius form block which is positively maintainedagainst disalignment with a complementary form shoe.

Other objects will become apparent to those skilled in the art in thelight of the following description and accompanying drawing.

In accordance with this invention, generally stated, a

tube bending machine is provided with a rotating radius form block and arectilinearly moving complementary form shoe, each having a groove whichembraces respectively diametrically opposite sides of a tube being bent.At least one of the grooves is circularly arcuate and has a radius lessthan the radius of the tube being bent. Preferably, the radius formblock is mounted on a spindle which is rotated by a bull wheel from.which the spindle can be readily pulled. A pinion, mounted on thespindle, serves to drive a rack plate upon which a form shoe is mountedin such a way that it can be readily removed and replaced.

The end of the spindle opposite the.bull wheel is journaled in a hearingwhich is arranged to be swung out of the way to permit the spindle to beremoved from the bull wheel. The bearing counteracts the tendency of thespindle to disalignment under the thrust of a tube being bent.

The hull. wheel is driven by a worm gear which may be rotated by turningeither of .two shafts. extending at United States Patent 2,986,195 e e y21??? right angles to one another and which may provide ferent gearratios.

Especially in bending thin-walled tubing of small diameter, provision ismade for positively inter-engaging the radiusform block and the formshoe to ensure align.- ment of the forming grooves.

In the drawing,

Figure 1 is a top plan view of a tube bending machine constructed inaccordance with one embodiment of invention;

Figure 2 is a view in end elevation of the machine shown in Figure 1;

Figure 3 is a fragmentary view in side elevationof the device shown inFigure 1,, showing the right side of the device as viewed in Figure 1;

Figure 4 is a fragmentary view in side elevation of the device shown inFigure 1 showing the left side;

Figure 5 is a sectional view taken along the line 5-5 of Figure 4,showing the radius form block in partly rotated position with respect toFigure. 1;.

Figure 6 is a sectional view taken along the line 6+6 of Figure 1;

Figure 7 is a fragmentary top plan view with/the removable forming partsomitted, showing, in dotted lines,

the internal gearing; Figure 8 is a fragmentary sectional view takentilt ng the line 8-.S of Figure 5,, and showing a section of tub- ,ingin the forming grooves of the radius form block form shoe;

Figure 9 is a view in perspective of the tube clamp of the illustrativeembodiment;

Figure 10 is a bottom plan view of the form shoe; Figure 1.1 is a topplan view of the rack plate; Figure 12. is a view in perspective showingthe bottom and side of the embodiment of form shoe shown in Fig,-

ures 1-8;

Figure 13 is a view in perspective showing the top and side of a formshoe for use with small diameter tubes;

Figure 14 is a view in perspective showing a radiusform blockcomplementary to the form shoe shown in Figure 13, mounted on a spindleconstructed in accordance with one embodiment of this invention;

Figure 15 is a sectional view taken along the line 15-,-15 of Figure 2;

Figure 16 is a sectional view taken along the line of Figure 15; and VFigure 17 is a sectional view taken along the line 17- 17 of Figure 15.

Referring now to the drawing for illustrative embodiments of thisinvention, reference numeral 1 indicates a complete tube bendingmachine. The tube bending machine 1 is made up of a housing, on whichcertain fixed parts are mounted; forming members, includi g a rotatingform block and a rectilinearly moving forrn shoe; a clamp, by which thetube to be bent is clamped to the form block, .and drive mechanism,mainly within the housing, by which the form block is rotated. Thesevarious elements will be described in that order.

A housing 2 consists of a base shell 3 and a top shell 4,'connected bystuds 5. On the bottom of the base .shell 3 is a lug 6 by which themachine can be held .vertical leg 12 is also mounted on the top shell 4,

means of screws 14. The vise has a sliding jaw 16, moved back and forthalong the leg 11 by a screw 18 which extends through a threaded hole inthe leg 12. The jaw 16 has a brass or other bearing metal face plate 20,and an outwardly projecting foot 22. The horizontal vise leg 11 isT-shaped in cross section, and the jaw 16 is provided with a pair ofinturned flanges which engage beneath the head of the T-shape and thuspermit the jaw 16 to ride lengthwise along the leg 11 but prevent anyupward or sideways displacement of the jaw 16. is cylindrical post 24projects from the free end of the eg 12. t

A bearing bracket 90 is rotatably mounted at one of its ends on the post24, from which it is prevented from sliding axially by a retaining ring26. The bearing bracket 90 carries at its free end a sleeve bearing orbushing 91. A thumb screw 92 can be tightened against the post 24 toprevent the bracket 90 from sliding axially along the post.

In the drawings, two different embodiments of forming members, radiusform blocks and form shoes, are shown. Referring to the embodiment shownin Figures 1-12, and 17, a radius form block 80, with which a piniongear segment 81 is integral, has flat, parallel, top and bottom surfacesconnected by a peripheral face which is perpendicular to the surfaces. Ahole extends through the radius form block 80, with its axisperpendicular to the top and bottom surfaces.

' As shown particularly in Figures 1 and 5, the face of the radius formblock 80 has a circular section, centered on the axially extending hole,and extending through slightly more than 180.

7 The pinion gear segment 81 is concentric with the circular section.Another section of the face of the radius form block is tangent to thecircular section at a zero point, as shown in Figure l. Therebeyond, thecircumferential displacement of the circular section is indicated bygraduations on the top surface, as shown in Figure l. A pair of axiallyextending ears 130 (see Figure 4) project above and below the top andbottom surfaces respectively at the outer end of this tangential facesection. On the other end of the circular section, is another tangentialface section which, however, being more than 180 from the face sectionfrom which the ears 130 project, is not parallel with the latter. A flatsurface 132 connects the two tangential faces.

A forming groove 82 extends around the entire periphcry of the formblock 80 except for the surface 132. The forming groove 82 embraces afew degrees less than 180 and, in crosssection, is on a radius slightlyless than one-half the minimum allowable outside diameter of a standardsize tube to be bent, as shown in Figure 8.

A form shoe 105, for use with the radius form block 80, is rectangular,with flat, parallel top and bottom surfaces. The bottom surface of theform shoe 105 is provided with mortises 104, as shown in Figure 12,where the form shoe 105 is inverted. The mortises 104 are proportionedand arranged to receive tenons 102 on a rack plate 100. The rack plate100 has teeth 101 along one long edge, adapted to mesh with the teeth ofthe pinion gear segment 81. One of the flat sides of the form shoe 105is provided with a groove 106 which, like the groove 82 of the radiusform block 80, embraces a few degrees less than 180 and, in crosssection, is on a radius slightly less than one-half the minimumallowable outside diameter of a standard size tube to be bent, as shownin Figure 8. On the opposite face of the form shoe is another forminggroove 107, for use with a different diameter of tube and differentradius form block.

The embodiment of radius form block and form shoe shown in Figures 13and 14 is particularly adapted to use with thin-walled tubing of smalldiameter, for example from one-eighth inch to five-sixteenth inch,outside diameter, although it can be used with other sizes. It isadapted to maintain the alignment of the forming grooves so that norelative axial shearing movement between the form block and form shoe ispermitted. In this embodiment, a radius form block 70 has flat,parallel, top and bottom surfaces, connected by a face which isperpendicular to them, and a hole extending perpendicularly betweenthem. The face of the radius form block 70 has a circular sectioncentered on the axis of the hole and extending through slightly morethan 180". As was the case with the first embodiment of form blockdescribed, one section of the face of the form block 70 is tangent tothe circular section at a zero point. A pair of axially extending earsproject above and below the top and bottom surface respectively at theouter end of this tangential face section, as shown in Figure 14. On theother-end of the circular face section, is another tangential facesection which, however, being more than from the face section from whichthe ears 130 project, is not parallelwith the latter. A flat surface 132connects the two tangential faces.

A forming groove 72 in the face of the form block 70 extends around theentire periphery of the form block, except along the flat surface 132'.In this embodiment, on either side of the groove 72, the face isprovided with ribs 73 lying parallel with and extending coextensivelywith the groove 72.

A rectangular .form shoe 205 is provided along one of its flat sidefaces with a forming groove 202 corresponding with the groove 72 in theform block 70. On either side of the groove 202, the form shoe face isprovided with grooves 203 complementary with the ribs 73. In theembodiment of form shoe shown in Figure 13, a groove 207 is providedalong the side face of the form shoe opposite the side face along whichthe grooves 202 and 203 extend. As is the case with the form shoe 105,the form shoe 205 is provided in its bottom surface with mortisesadapted to receive tenons on a rack plate, and can be used for twodifferent sizes of tubing merely by turning it around, because the landsadjacent the grooves 202 and 203, like the lands adja cent the grooves106, 107 and 207, are fiat, and provide a sturdy and accurate bearingsurface against the face plate 20. The forming grooves in the radiusform block and form shoe of this embodiment, like those of theembodiment shown in Figures l-5, are of smaller radius than the tubes tobe bent.

Examples of radii of grooves in the form block and form shoe of theembodiment shown in Figures l-l2, for use with standard sizes ofthin-walled stainless steel tubing are:

CD. of Tubing Radius of Grooves (istandard (i.00l') manufacturingtolerances) Inches I nchea as s 247 $4 .308 as 370 4 Examples of radiiof grooves in the embodiment of form block and form shoe shown inFigures 13 and 14, for use with standard sizes of thin-walled, smalldiameter stainless steel tubing, are:

CD. of Tubing Radius of Grooves (istandard (=t=.001") manufacturingtolerances) Inches Inches .060 as .091 ids 122 A 153 fie The axiallyextending ears 130 on each of the embodiments of radius form block serveto retain a clamp 140. The clamp 140 is constructed in the form of ayoke with legs 141 and a connecting bridge 142. The inside surface ofthe legs 141 is cut away to form oppositely disposed laterally extendingchannels 147 and to define an inturned lug 143 at the end of each leg. Aclamping block 146 is wider than the legs 141 and taller than thedistance between the inside surfaces of the legs 1141 but shorter thanthe distance between the bottoms of the channels 147 in the legs 141, sothat the clamping block may be slipped between the channels 147. The topand bottom faces of the clamping block 146 are cut away to form channelswithin which the legs 141 between the channels 147 and the bridge 142are received, as shown in Figure 9. Opposite faces of the clamping block146 are provided with laterally extending grooves corresponding with theforming grooves of the form shoe with which they are to be used. Anadjusting screw 144 extends through a tapped hole in the bridge 142. Theend of the adjusting screw 144 which extends between the legs 141carries a plate 145 which fits closely but slideably between the legs141 and bears against the clamp block 146. The other end of theadjusting screw 144 is adapted to take a wrench.

The radius form block 80, the embodiment shown in Figures 1-8, 12 and17, is keyed to a form block carrying section 64 of a spindle 60. Thesection 64 extends through the hole in the form block 80. Beyond theupper surface of the form block 80 the diameter of the spindle 60 isreduced to provide an upper bearing section 65 with a shoulder betweenit and the form block carrying section 64. The form block 80 rests on anannular shoulder formed by the enlargement of the diameter of thespindle 60. A further enlarged diameter of the spindle 60 defines anintermediate bearing section 63. Below the intermediate bearing section63, the spindle 60 is grooved axially to provide splines 62. Thelowermost part of the spindle 60 is reduced in diameter to provide anannular bearing shoulder 66 and a lower bearing section 61.

The embodiment of radius form block 70 and a pinion gear segment 71,shown in Figure 14 are keyed to a spindle 60, similar to the spindle 60upon which the form block 80 is mounted.

As shown particularly in Figure 17, the spindle 60 is journaled withinthe housing 2, with the lower bearing section 61 of the spindle in aball bearing 51, and the intermediate bearing section 63 journaled in aneedle bearing 52. Above the radius form block, the upper bearingsection 65 is journaled in the sleeve bearing 91 of the bearing bracket90. As shown in Figures 4 and 6, the post 24 upon which the bearingbracket 90 is mounted, is sufficiently tall to permit the bearing 91 tobe lifted above and swung clear of the upper bearing section 65.

Inside the housing, between the ball bearing 51 and the needle bearing52, the splines 62 of the spindle 60 mesh with complementary internalsplines 54 of a bull wheel 50. The bull wheel 50 is drh'en by a wormgear 43, as shown particularly in Figure 15. The worm gear 43 is keyedto a shaft 41. The shaft 41 is journaled at its end adjacent the wormgear 43 in a sleeve bearing mounted in a suitable boss in the housing 2,as shown in Figure 15, and at itsv other end, in a ball bearing 42. Theshaft 41 projects beyond the bearing 42 and outside of the housing 2,where it is provided with a squared end 45 upon which a wrench may beput. Between the bearing 42 and the worm gear 43, a helical gear 40 iskeyed to the shaft 41.

A helical drive gear 30, the teeth of which mesh with the helical gear40, is mounted on a shaft 31, the axis of which is at right angles tothe axis of the shaft 41. The lower end of the shaft 31 is journaled ina ball bearing 34 mounted in a suitable boss .in the base shell .31projects through and beyond a boss in the top shell 4. The projectingshaft 31 is provided with a squared end 35 so that a wrench can be puton it. The number of teeth on the drive gear 30 may diflier from thenumber on the helical gear 40, so that greater or less rotational speedcan be imparted to the shaft 41 by turning the shaft 31 than by turningthe shaft 41 directly.

A ratchet-type box wrench 15, as shown in Figure 1, can be used oneither the shank 35, to turn the shaft 31, or on the shank 45, to turnthe shaft 41 directly.

In the operation of the tube bending machine of this invention, with theembodiment of radius form'block and form shoe shown in Figures 1-12,assuming that the machine is assembled as shown in Figures l-6, that alength of tubing is in place, with one end of the tubing clamped to theradius form block by means of the clamp 146, as indicated in Figure 5,and that the various parts are in the position shown in Figure 1, it isonly necessary to put the wrench 15 on the squared end 35 of the shaft31 in such a Way that the wrench acts in a clockwise direction as viewedin Figure 1, and to turn the shaft 31. The turning of the shaft 31rotates the gear 40 and the shaft 41, rotating the worm gear 43 and thebull wheel 50. The turning of the bull. wheel 50 rotates the spindle 60,hence the form block 80 in a clockwise direction as viewed in Figure 1.The form block is shown as having been rotated through an arc ofsomething less than in Figure 5. As is most clearly shown in Figure 6,the form block 80 and the rack plate are aligned horizontally, with theteeth of the pinion gear segment 01 meshed with the teeth 101 of therack plate. The rack plate rests upon and slides along the foot 22 ofthe jaw 16. The rack plate is thus moved rectilinearly along the bearingplate 20 by the pinion gear segment 81, as the radius form block 80 isrotated. As shown in Figure 8, the tubing being bent serves to hold theform shoe and radius form block in alignment. This is entirelysatisfactory in the larger sizes of tubing for which the radius formblock 80 and the corresponding form shoe 105 are used. As the radiusform block is turned, the tubing is pulled into the groove 82 which, ashas been explained, is of slightly less radius than the tubing. Thistends to compress the tubing along a vertical diameter as viewed inFigure 8, which overcomes the tendency of the tubing to collapse alongthe horizontal diameter as viewed in Figure 8. The net result of thebend produced by the device of this invention, is to reduce the diameterof the tubing slightly, but to produce a substantially round sectionthroughout the bend.

In order to remove the bent tubing from the machine, the clamp screw 144is backed off to release the end of the tube and permit the clamp to beslipped off the ears 130. The vise screw 18 is backed off a shortdistance to relieve the pressure of the form shoe 105 on the tubing. Thetubing is then either simply slipped out between the form shoe and theform block or, if the tubing is long or has other bends in it or isbeing bent in place after it is installed, the thumb screw 92 of thebearing bracket 90 is loosened, the bearing bracket 90 is lifted untilthe bearing 91 is clear of the upper bearing section 65 of the spindleand is swung to one side and the screw 18 is backed off until the tubingcan be removed from between the form shoe and the form block.

If, now, it is desired to bend a length of tubing of a larger diameter,corresponding with the forming groove 107 of the form shoe 105, the formshoe 105 is simply lifted from the rack plate 100, turned around, andseated again on the rack plate, with the tenons 102 taking into themortises 104. The radius form block 80 is slipped axially from thespindle 60, and another radius form block, with a forming groovecorresponding to the forming groove 107, is slipped into place. Thebearing bracket 90 is swung into place and the thumb screw 92 istightened.

'sponding to the groove 107 in operative position.

The radius form block is turned to the zero position as shown in Figure1 by turning the shaft 31 counterclock wise. Alternatively, before thebracket 90 is in place the spindle 60 can be lifted from the housing 2,turned until the form block is properly directed, and replaced. If thesplines do not mesh in exactly the proper position, the shaft 31 can beturned in either direction to properly orient the form block. The tubingis positioned between the form block and form shoe, either by insertingthe end of the tubing between them or by swinging the bearing bracket 90to one side, and in effect assembling the form block and form shoearound the tubing. The clamp block 146 is removed from the clamp, turnedaround, and reinserted between the legs 141, with the groove corre- Thelugs 143 are slipped behind the ears 130, with the end of the tubingbetween the groove in the radius form block and the groove in the clampblock 146, and the screw 144 is tightened until the end of the tubing issecurely clamped.

With large diameter tubing, it is frequently desirable to place themachine in a vise, with the lug 6 gripped between the jaws of the vise.In the event that the gear ratio between the gear 40 and the gear 30 isless than 1 to 1, it will probably be desirable to put the wrench 15 onthe squared end 45 of the shaft 41 and turn the shaft 41 directly, in aclockwise direction. as viewed in Figure 3, to exert the greatest amountof force on the radius form block.

Within limits, the gear segments carried by different radius blocks canbe uniform, so that the same rack plate can be used with form shoescarrying forming grooves of various sizes. However, it may be necessaryor desirable to use different rack plates with difierent sizes of tubingor it may be desirable to use different rack plates with the same sizesof tubing made from difierent materials. For example, if it is desiredto produce either a small overtravel or undertravel of the form shoewith respect to the form block, gear segments of difierent radii andrack plates of diiferent widths can be used with form blocks and formshoes having forming grooves of the same radii.

If, now, it is desired to bend a tube of small diameter, the radius formblock and the spindle 60 are removed, and the spindle carrying the formblock 70 is slipped into place. The radius form block 70 is brought toits zero position by turning either the shaft 31 or the shaft 41 in theappropriate direction. As can be seen by comparing the pinion gearsegment 71 as shown in Figure 14 with the pinion gear segment 81 asshown in Figures 3 and 5, a different rack plate, with teethcorresponding to the teeth of the gear segment 71, will have to be used.The appropriate rack plate is simply laid on the foot 22 and the formshoe 205 is seated on the rack plate, with the tenons of the rack platetaking into the mortises in the form shoe. A tube to be bent is insertedbetween the form shoe 205 and the form block 70, the clamp 140 is putinto place, with a suitable clamping block with grooves complementary tothe ribs 73 and a groove corresponding with the groove 72, and theclamping block is clamped tightly against the end of the tube. The screw18 is turned down until the jaw 16 has moved the form shoe 205 into snugengagement with the tube to be bent, the tube lying within the grooves72 and 202. In this posture, the ribs 73 will extend within the grooves203. When the radius form block 70 is turned, the engagement of the ribs73 with the walls of the grooves 203 ensures against any disalignmentbetween the form shoe 295 and the form block 70. This is especiallyimportant with thin walled tubing of small diameter which mightotherwise be flattened between the form shoe and form block or subjectedto shearing forces if the form shoe and form block should move axiallyrelative to one another. As can be seen from Figures 3, 6 and 8, a smallgap is left between the form shoe and the form block by virtue of thefact that the forming grooves are of smaller radius than the tubing tobe bent, and this situation aggravates the problem of maintainingalignment when tubing of small diameter is being bent.

Numerous variations in the construction of the tube bending machine ofthis invention, within the scope of the appended claims, will occur tothose skilled in the art in the light of the foregoing disclosure.

Preferably the gearing of the drive gear 30 is such that one revolutionof the shaft 31 will turn the shaft 41 through more than one revolution,for example one and a half revolutions. This is particularlyadvantageous in bending small diameter tubing, when the machine need noteven be put into a vise. As has been pointed out in connection with theoperation of the machine, a length of tubing can be bent in the middleas well as at one end, and can be bent in place, since the clamp 140 andthe form shoe can be put in place around a tube to be bent, anywherealong its length. The swinging bearing bracket permits of thisarrangement, and at the same time furnishes support to the spindleagainst the side thrust exerted by the tubing against the radius formblock.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. In a tube bending machine in which the tube to be bent is clampedbetween a rotatable radius form block and a cooperating form shoearranged for rectilinear movement in a direction substantiallytangential with respect to the radius block, said form block and formshoe each having opposed faces with a forming groove for embracingrespectively the diametrically opposite sides of a tube being bent, saidradius form block being mounted to permit axial displacement thereofwith respect to said form shoe, the improvement comprising, a rib in oneof said opposed faces and a complementary shaped rib receiving grooveformed in the other of said opposed faces both spaced an equal distancefrom the forming groove in the form block and in the form shoe andlocated on said opposed faces spaced from the edge of said form blockand said form shoe, said rib and said complementary shaped rib receivinggroove being engaged during tube bending process to prevent disalignmentof the forming groove in said form block and the forming groove in saidform shoe 2. In a tube bending machine having a rotatable radius formblock and a rectilinearly moving form shoe having opposed faces on eachprovided with a forming groove, the improvement comprising a rotarymounting for the radius form block constructed and arranged to permitaxial movement of said radius form block with respect to said mounting,a rib on one of said opposed faces and a complementary shaped ribreceiving groove formed in the other of said opposed faces both spacedan equal distance from said forming groove in said form block and insaid form shoe and located on said opposed faces spaced from the edge ofsaid form block and said form shoe, said rib and said complementaryshaped rib receiving groove being engaged during the tube bendingprocess to prevent disalignment of the forming groove in said form blockand the forming groove in said form shoe.

3. In a tube bending machine of the character in which the tube to bebent is clamped between a rotatable radius form block and a cooperatingform shoe arranged for rectilinear movement in a direction substantiallytangential with respect to the radius form block, said form block havinga groove for embracing one side of a tube being beat, the improvementwhich comprises means defining a pair of tube-embracing grooves one eachon opposite sides of said form shoe and a supporting face on a thirdside thereof, a plate having gear teeth along one edge, a face on saidplate adjacent said edge, symmetrical cooperating male and femaleselectively engageable means on the faceof said plate and on thesupporting face on said third side of said form shoe whereby said formshoe may be reversed end for end and detachably located on said platewith either of said tube embracing grooves adjacent the radius formblock groove, said radius form block being removable and replaceable andprovided with a gear segment having gear teeth meshing with the gearteeth on the said plate, whereby, when the said form block 5 is rotated,the plate and the form shoe are driven by the said gear segment.

References Cited in the file of this patent UNITED STATES PATENTS986,654 Tattu Mar. 14, 1911 10 Oddie Nov. 9, 1926 Abramson Nov. 21, 1933Parker Dec. 22, 1942 Lampe Aug. 13, 1946 Tirone Oct. 5, 1954 Franck Feb.15, 1955 FOREIGN PATENTS France Oct. 1, 1920 Great Britain Dec. 3, 1928

